Judges 16:9

Now there were men lying in wait, in ambush, abiding with her in the chamber, for she had permitted a Philistine spy to conceal himself in the inner apartment. And she said unto him, The Philistines be upon thee, Samson. And he, momentarily brought back to his senses by her cry of treason, brake the withes as a thread of tow is broken when it toucheth the fire, when it is brought near enough to feel the fire's heat. So his strength was not known.